Snap action constant level device



Patented Nov. 13, 1945 UNITED STATES EN T iO FFI CE SNAP ACTION CONSTANT, LEVELDEVICE Lourdes V. McCarty,'Milwaukee, Wis.,'f'assignor to Automatic Products Company, Milwaukee, Wis., acorporation of :Wisconsin v Application November 5, 1943, SerialvNo. 509,097

Claims.

This invention 4relates in general to devices for controlling the supply of liquid 'fuel from a reservoir to a burner of the gravity feed type, and more `particularly to a, device for maintaining a constant level in a chamber intermediate the reservoir and burner and thereby 'maintaining a desired flow of fuel actually supplied to the burner. L

In gravity feed type burners for'liquid fuel, the burner can be operatedproperly only if supplied with the desired flow or required quantity of fuel, andvsuch flow or quantity is most readily obtained by controlling the level of the Lfuel in a chamber ahead of the burnerto secure a constant hydrostatic head. The constant level can readily Vbe maintained by adjustment of va valve controlling ow of the liquid'fuelinto the chamber. Such valve adjustment is obtainable by constantly biasing the inlet valve in the open position 4and by employing a float or floats to move the valve toward or into yclosed position as the level of the fuel changes. When the heating system is used on a vehicle on either land or water, the entire system is subject to tilting rela-- tive to the normalhorizontal position whichdis turbs the operation of the oat'and also increases the resistance of the inlet valve to'closure-by the lloat.`

It is therefore an object of the present invention to provide means for vmaintaining a constant level of liquid fuel in a chamber between a, reservoir and a-burnereven though the chamvber may be tilted from'the normal horizontal position.

Another object of the invention is to provide a liquid'fuel-control device in which 'the level of the fuel in a chamber is controlled by `a floatactuated snap-action means Vfor closing the inlet valve into the chamberregardless of the tilting of .the device from the normal position thereof.

Another object of .theinvention is :to provide a constant liquid Vfuel level control device in which the level of the fuel in a chamber is controlledby a oat or float system vhaving different displacement portions `for actuating `a toggle mechanism to snap; from one'position to another position upon riseinithe oil level, even though the chambery is tiltedup to thirty degrees 'from its normal horizontal position.

Objects and advantages other than 'those above set forth will be apparent Afrom the following description `.when read in connection with thexaccompanying drawings, in which:

Fig. 1 is atop'plan view of a constant ylevel device embodying 'the present invention, the cover thereof vbeing removed anda portion of the supporting ,bracketfor the internal structure being cut away to show the arrangement ofsuch structure more clearly.; i

Fig. "2 is a vertical cross-'sectional View taken s on theplane of line 2--42 of Fig. 1 'toshovv` thearrangement and constructionparticularly of the neat system and the toggle mechanism operated thereby, the view illustrating the position of such parts at the normal oil'level;

Fig. 3 is a view similar to Fig. 2 but illustrating indotted lines the .position of the parts in the first lof the two steps requiredin coming to high ollevel and illustrating in full lines the secondof .the ,steps required of the mechanism in coming to high oil level;r

2Fig. 4 is a vertical sectional view taken on theplane of line 4-4 of Fig. 2 and looking from the left -atf the vendof thefconstant level device;

v5 ifs a Vertical, sectional viewtake'n on the plane of' line 5-5 of Fig. Zand looking from the left; 'and -Fig..6 is 'a perspective view showing the float system and toggle mechanism separated from all other parts of the device.

Referring more particularly to the drawings by character-'sof reference, the reference numeral I0 designates a casing enclosing the other portions of'` the device within an oil supply cham-` ber II Vin Which'the oil level isto be vmaintained substantially constant, the casing having formed therein portions ofthe conduits by which 'the oil flows to andawayfrom the chamber II. The oil .flows into `the casing I0 from a reservoir by way of a conduit (neitherof which is shown) connecting with passage-Ways I2, I3, and I4 formed in the wall of the casing. The vertical inlet vpassage I4 is threaded internally to receive `a valve housing I6 of generally cruciform shape having ,communicating axial and longitudinal passages therethrough to receive theinlet valve body I'I shown as being of the needle v valve type and seating on the edge formed by the intersection of the axial and longiudinal passages in the valve housing. The .valve I1 controls .the flow ofoil into the chamber II and is biased toiwardopenposition by aspring I8 seated between the lateral arms of the valve housing I6 and a nut 2l.` Then'ut threadedly engages a sleeve 22 which is -pressed or otherwise secured on the upper stem portion of -the valve I6 and is held in predeternlined'position by a spring 23 acting between the nut 2I and a peripheral flange on the upper end of the sleeve 22. The nut 2| has therefrom, is mounted in the casing I by screws 23 extending through the top portion of theY bracket at one end thereof and through lugs extending laterally from the lower edges of the A iioat lever, generally shaped` as a yoke, in-

cludes side bars 32 connected byar central bar 33 and is pivotally mounted on the pin 3| .and extends around the inlet valve I6, I1. The connecting yoke Ybar 33 has ears34 depending therefrom" and provided with apertures 'for receiving the ends'of asubstantially U-shaped member 34 resting on and engaging the sides of the adjusting nut 2I and formed with Van aperture to allow the stem "portion of the v alve I6 to extend upwardly therethrough. The U-shaped member 35 isprovided'at the ends thereof with lateral ears extending into and engaging in apertures in the ears' 34 of the float lever o'r'yoke 32, 33. YAsA shown, member 35 is held in contact with the upper side of the nut 2| by the spring 23 and, due to' itsconnection with the oat yoke, holds the nut'2l againstturning, thus making it possible to adjust the inlet'valve by turning the valve'itself. The connection between the member 35 and the oat yoke 32, 33 causes closing of the valve I6 responsive to movement of a Viioat system which lifts the end of the yoke 32, 33 and exerts a downward pressureby way of the connecting member 35 on the valve. -The side bars 33 of the float yoke are provided with trunnions 31 extendingzinwardly from the yoke s ide bars and serving as mounting and pivoting points for a frame 38 having. floats 4I and 42 extending downwardly from the' router ends thereof. Floats 4I, 42'are1substantially parallelogramsin shape fand are fastened to the Yframe Y38 at the ,upper or top sides of such floats in substantially the samepositions. Itwill be observed, however, that oat42 is substantially largerthan float 4I, kand displaces more oil than can bedisplaced bygoat 4I. Floats 4I and, 42, may, of course, be made integral so long anoat portion 42 is made larger than' iioat portion-,4I for the purpose of securing continuing buoyancy of oat portion'42after portion 4I4 is submerged;V

Theend of the float frame 3B, towhich the iioat 42 kis secured, is also provided with arms or ears 45 extending vupwardly from theframe and in'- wardly toward thecenter of the frame to provide stops for an Yover-center toggle mechanism. The toggle mechanism comprises arms 5I pivotally mountedV on trunnionsv 31 and joined byda connecting bar 52. Each of the toggle arms is provided with a weight 53 extending inwardly from the arms and at a substantial distance from a vertical plane through the center of the trunnions 31. The connecting bar 52 has a portion 54 extending upwardly and inwardlytherefrom to provide a vconnecting point for one end of a helical spring'55 under tensionwhich is connected at the other end'with the portionjof theoat 38;

extending across the top of the float 4I. The spring 55 is, of course, oiset to one side of the center line through the entire device to avoid interference with other portions of the structure. Theupper ends of the toggle arms 5I extend toward the float 42 for a sufficient distance to engage the stops 45 when the toggle arms are in a position corresponding to normal oil level, as shown in Fig. 2, or high oil level, as shown in dotted line in Fig. 3. The floats, float frame, and lever and the toggle mechanism together form a iioat system which moves to give closing force to the inlet valve. 4

A tubular extension 6I rises from the bottom of thecasing' I0 and provides a discharge passage 62 leading from the oil supply chamber II and connected byV a suitable pipe with a burner (neither of which is shown). A metering valve 63 extends into the discharge passage 62 and is formed with a shoulder G4 to rest on a seat formed at the upper end of the discharge passage 62. The metering valve is tubular for at least a portion of its length and has a metering slot 65 cut into the lower end thereof moving in the discharge passage 62 and has a venting aperture (not shown) above thehigh oil level. The metering valve is of the construction shown in Patent 2,183,815 issued to Roy W.' Johnson on December 19, 1939, land accordingly need not be further described.

In operation, when the'oil is at the normal level, as shown in Fig. 2, the toggle arms 5I rest on the stops 45 and the central axis of the spring 55 is abovefthe horizontal line .through the center of the trunnions 31 atallv times and hence opposes the tendency of the weights 53 to move the oat system in a clockwise direction. 'The' portlonrof the effect of the weights 53,`which is not balanced by the spring 55, is balanced by the displacement of the float 42 in excess of the displacement of the iioatV 4I'. In other words, the mechanism is an over-center toggle in which the position of the weights instead` cfa springy determines the position of the mechanism.` Inthe normal position, the forceto be voverc :orne by the displacement of the float 42, plusthe tension of the spring 35is the clockwise turning moment of the weights 53, due to the action of gravity, times the length of the lever -arm from the center of the trunnions 31 to the axis through thecenter ofk gravity of the weights 53. So long as the oil is at the normal level the excess displacement of the iioat 421s suiicient only to keep the float system in balance and no movement thereof takes place. i

However, when'the oil level' rises,'the float system also rises Yand a. pressure is exerted by -way of the yoke 32, r33 on the inlet valve I6 to tend to force the valve into closed position. But if the valve I6 sticks in its housing, or is held for any other reasonthe oil level continues to rise until the float 4I is submerged and accordinglylno longer contributes any buoyancy to'the float system. Displacement fof the oat 42, however, in"

creases and overbalances the eiect of the weights 53 suiiiciently to move the' entire float system and the toggle mechanismcounter-clockwise into the dotted line position a shown inFig. 3. The turning moment ofA the weights '53'is now less/than heretofore because the lever arm from the trunnions 31 to the axis of gravity of the weights is shorter and the spring 55 therefore snaps the toggle mechanism clockwise into the fullY line position b, also shown in Fig. 3, The .toggle arms 'then' bear on the'tubular outlet'extensionij and iare stopped in position b.; (iIt willjbeapparentythat the stoppingfunction of the extension .6l may besperformed byother; stops if the dimensions'of the device :are lsuch '.-that the f extension 6l is fno longer inthe proper location to perform its functionfas a stop.) The entirefloat systemandthe toggle? mechanism are now liftedga'bove .the normal-position duei-to Athe action ofthe springz55 on the toggle mechanism. VA downward force is therefore exerted on .the valve ,1,6 sufficient to overcome any ordinary sticking Y,of the valve-and to close* the Vvalve :as soon Vas any obstruction :on tsseat: is removed. g Y A :It will VbeseenV that the present invention `pr-ovides a chamber in -which a constantxhydrostatic head ofiuel is maintained,Y thereby maintaining a desired oWin the fuel actually supplied tothe gravity-.fed burner. The fuel level `is controlled by a floatqsystem having unequal portions and moving an inlet valvetoward closed'position vagainst the'bias of a valve-'opening spring. ,And the-iioat system is subiected'to a snap action toggle mechanism actingafter :the ifloat systemhas exerted on the valve all of the force possible due .to normal rising `of the liquid level. lThe particular advantageof the present device is that the device as a whole may Vbe either temporarily or permanently positionedY as muchas thirty degreesfrom horizontal -without vany eiect whatever on the trippingof the oat system .whenthe loil level rises over the pivot v,poi-nt of .the oatsystem; that is, there will be the same dilerence between normal level and high level of the oil regardless of the angular displacement of the device up to a limit of thirty degrees. The operation of the device is accordingly unaffected When used on vehicles Where the vehicles are stopped on slopes of less than thirty degrees, or when used on boats where the movement of the boat is within the above limit of angular relation to the normal position.

Although but one embodiment of the present invention has 4been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. In a constant liquid level control device, a casing defining a chamber having inlet and outlet passages, a valve controlling the flow of liquid through the inlet passage into the chamber, a float system buoyed up in the liquid in the chamber and having portions of unequal displacement, a yoke pivotally connected with said float system and connected with said valve to transmit a force thereto upon rising and rocking movement of said iloat system, and a toggle mechanism pivotally mounted on said noat system and actuated thereby by rocking thereof to impart a force to said yoke;

2. In a constant liquid level control device, a casing defining a chamber having inlet and outlet passages, a valve controlling the oW of liquid through the inlet passage into the chamber, a float system buoyed up in the liquid in the chamber, said system including portions of diierent displacement, a yoke pivotally connected with said iioat system and connected with said valve to transmit a force thereto upon rising movement of said oat system, and a toggle mechanism pivotally mounted on said oat system and actuated thereby to impart a force to said yoke, said toggle mechanism being biased toward the float portion of larger displacement.

3. In a constant liquid level control device, a

casing dening a chamber having inlet and foutlet passages, `a valve controlling thezflow nrzliquid' through the `inlet passage into =thechamber,fa float systemi having portions of dilerent displace,- ment buoyed upin the liquid in the `chambena yoke pivotallyconnected with said float system and connected Withsaidava-lve to transmit-afford@ thereto upon-rising movement of said 'iloatfsystem, and .a toggle mechanism pivotallymounted on said float system and/actuated thereby-)to impart a force to said yoke, saiditogglezmechanism including weights biasing said 'toggle mechanism in a direction opposite to thatv ofthe effect-ofthe larger displacement oatportion.

4. In a .constant liquidlevel control device.,-.a casing defining a chamber having inletand outlet passages, a valve controlling the'ilowfofzliquid through the inlet passage into thechamber,Jav lioat system having portions of diiierent displacementbuoyed up fin the liquid in the chamber, a yoke pivotally connected with said float system and connected with saidyalve to transmit a force thereto upon rising movement of said float system, a toggle mechanism pivotally mounted on said iioat-system and actuated there` by to impart a force to said yoke and including arms pivotally mountedon saidyoke,fandiweights mounted on the yarms and biasing said mecha nism toward fthe larger displacement iioatzportion.

5. .In a constant liquid 'level :control -device,a

casing defining a chamberhaving inlet and outlet passages, a valve controlling the liow of liquid through the inlet passage into the chamber, a iioat system having portions of different displacement buoyed up in the liquid in the chamber, a yoke pivotally connected with said float system and connected with said valve to transmit a force thereto upon rising movement of said 40 float system, a toggle mechanism pivotally mounted on said float system and actuated thereby to impart a force to said yoke and including arms pivotally mounted on said yoke and extending upwardly therefrom and toward the float portion of larger displacement, and weights mounted on the arms at the upper ends thereof.

6. In a constant liquid level control device, a casing defining a chamber having inlet and outlet passages, a valve controlling the iiow of liquid through the inlet passage into the chamber, a oat system buoyed up in the liquid in the chamber, said system including portions of different displacement and stops extending upwardly from the larger displacement float portion, a yoke pivotally connected with said float system and connected with said valve to transmit force thereto upon rising movement of said oat system, and a toggle mechanism pivotally mounted on said float system and including arms pivotally mounted on said yoke and extending upwardly therefrom and toward the iioat portion of larger displacement, the upper ends of the arms resting on the stops extending from said float system in the normal level position thereof, and weights mounted on the arms and biasing said mechanism toward the larger displacement iioat portion.

7. In a constant liquid level control device, a casing delining a chamber having inlet and outlet passages, a valve controlling the flow of liquid through the inlet passage into the chamber, a oat system buoyed up in the liquid in the charnber, said system including portions of different displacement, a yoke pivotally connected with ,said float system and connected With said valve to transmit a force thereto up'on rising movement of said iioat system, and a toggle mechanism pivotally mounted on said iioatsystem and actuated thereby to impart a 'force toY said yoke, said toggle mechanismy being' biased toward the iioat portion of larger displacement and including a spring connected Withthe 'oat portion of smaller displacement, the line of ac'- tion of the spring being above the pivot "point of said toggle mechanism.

8. In a constant liquid level control device, a casing deninga chamber having inlet and outlet passages, a valve controlling the iiow of iiquid through the inlet passage into the chamber, a lloat system having portions of different displacement buoyed up in the liquid in the chamber, a yoke pivotally connected with saidiioat system and connected with said valve to transmit a force thereto upon rising movement of said float syshaving its line of action above the pivot point ofv said yoke and opposing the bias of the Weights.

9. In a constant liquid level control device, a casing defining a chamber having inlet and outlet passages, a valve controlling the iiow of liquid through the inlet passage into the chamber, a

iloat system buoyed up in the liquid in the chamber, 'the oats being ofdiffer'ent volume,'a yoke pivotal'ly connected! with said oat system and connected with said Vvalve to transmit a force thereto upon 'rising movement of said iioat systemyand artoggle mechanism pivotally mounted on said floatsystem and actuated thereby to impart a force to said'yoke, said toggle mechanism including "weights biasing said mechanism in a direction "opposite to that of the effect of the larger displacement float portion, and including a khelical spring under tension and connected with the oat portion of smaller displacement, the center line of the spring always being above the pivot point of said toggle mechanism.

10. In a constant liquid Vlevel control device, a

vcasing defining a. chamber having inlet and outing its line of action above the pivot point/sof said yoke and opposing the bias of the weights. LOURDES V. MCCARTY. 

